Combustion heating control system



Nov. 3, 1953 F. B. AUBERT 2,657,742

COMBUSTION HEATING coNTor. SYSTEM Original Filed July 26, 1943 INVENTORJug, ATTORNEY Patented Nov. 3, 1953 UNITED STATES PTENT OFFICE Originalapplication July 26, 1943, Serial No.

496,099, now Patent No. 2,484,602, dated October 11, 1949. Divided andthis application September 10, 1949, Serial No. 115,063

2 Claims.

This invention relatesto new and useful improvements in heatingapparatus and more particularly to a heating control system therefor.

An object of the invention is to provide a heating apparatus which isparticularly adapted for the heating of enclosed spaces in aircraft suchfor example as the cabin or fuselage.

Another object is to provide a control system for initiating andcontrolling the burner operating cycle.

Another object is to provide a control by which the supply of fuel isincreased upon an increase in the rate of supply of combustion air.

Another object is to provide a control system in which the combustionair pressure controls the starting and stopping of a combustion airblower.

Another object is to provide a control system including means assuringoperation of the fuel igniting means prior to the supplying of fuel.

Another object is to provide a control system having a timed control forthe heating apparatus.

The invention consists in the improved control system, the cooperativerelation of parts and their agroupment in cooperative relation, to bemore fully described hereinafter and the novelty of which will beparticularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of thisspecification, there is clearly and fully illustrated a preferredembodiment of this invention, in which drawing:

The figure shown is a diagrammatic view of an electric control systemfor heating apparatus.

Referring to the drawings by numerals of reference there is shown aheating control system having an electrically driven timing motor andcontrol therefor. This control system is particularly adapted for use inconnection with the heating apparatus shown in my copending applicationSerial No. 496,099, filed July 26, 1943, now Patent 2,484,602, issuedOctober 11, 1949, of which this application is a division.

In this heating control system there is provided a fuel pump 43'! forsupplying fuel to a burner which is not shown. The fuel is ignited inthe burner by a hot wire resistance igniter 414. The combustion air forthe burner is supplied by either a ram air duct (since this apparatus isdesigned for use in a moving vehicle) or a blower 430. The blower 430 isnormally energized when insufficient ram air is being supplied and isstopped by a pressure responsive switch 43I responsive to ram airpressure.

There is a main switch 400, which is a double lows:

2 throw manual switch having an operating extension or lever 40!operatively connected to its switch arm 402 which is moved to the left,for starting the burner, to engage the switch arm contact with the fixedswitch contact 403. The closing of switch 400 completes a circuit fromthe battery or source of current supply 404 through the lead wire 405 toand through the switch 400 and thence through lead wire 406 to oneterminal of the coil 40? of the timing motor controlling relay switch408. From the other terminal of coil 401, a lead wire 409 extends to theswitch arm 4l0 of a normally closed snap acting cam operated switch 4!I. tact 4 l2 of the snap acting switch 4! l a lead wire 413 connects toone terminal of the hot wire igniting means 4 which has its otherterminal connected to ground. Operation of switch 400 to close circuitthrough its contact 403 therefore energizes the igniter 4M and actuatesthe relay switch 400, provided the igniter circuit is complete and thecurrent supply is suflicient to actuate the relay switch 408. Theoperation of relay switch 408 pulls the relay switch arm 4l5 intoengagement with the fixed relay contact M6 to close the circuit of thetiming motor 4!! as fol- From main switch lead wire 406 through leadwire M8, to relay switch arm M5 and its engaged contact M6 to lead wire419, connected to the closed contact 420 of the normally closed camoperated snap acting switch 42!, having its movable switch arm 422linked for movement in unison with switch arm 4|0. From the switch arm422 a lead wire 423 extends to one terminal of the timing motor 4H,which has its other terminal connected to ground by a lead wire 424.Energization of timing motor 4!! drives its cam member 425 to move thecam clockwise, as indicated by the directional arrow, to move cam 420out of holding relation to the cam follower thrust member 42! so thatthe snap acting switches 428 and 420 are moved to closed position.Closure of the blower control switch 428 completes a circuit to thecombustion air supplying blower motor 430 through the combustion airpressure responsive or ram switch 43! as follows: From battery lead wire405 through lead wire 432 to the fixed contact of switch 420, and fromits cam operated switch arm 433 via lead wire 434, to the normallyclosed contacts of ram switch 43! and therethrough to the lead wire 435connected to one terminal of the blower motor 430 having its otherterminal connected to ground by lead wire 436. The main switch 400, uponengagement with its contact 403, also controls the motor of the fuelFrom the fixed conpump motor 431 as it is in series circuit with the lowspeed fuel pump switchearm-EMZ byziead-wvire 443, connected to lead wire434. Closure of relay switch 438 engages the arm 442-witn fixed-contact444, thereby completing the-lcircuit -to.:one

terminal of the pump motor 431-via5 leadrwire1 445 having therein thelow speedrresistance flfi, the other terminal of the pump motorbeingconnected to ground by lead wire 44?. The heating apparatus willnow be in operation at low fuel consumption to supply the desired amountof heat in accordance with the-combustion=air supplyprovided by theblower. Upon increase in' 'the pressure of the combustionair abovethe-pressure provided by the blower, such-aswvill occurwvhen the vehicleis in rapid movement, theram-switch ,43 I will break circuitbetweemthe-blowe'r motor supplying lead Wires '434 and"435-an-d-willmake circuit from the lead'wireto the lead 446 connected tothe switch':arm449 of relay switch 433 arid movable in unison withthe-switchar-m 442. Since thesWitch-arm" 449 is in engagement with fixedrelay contact 458, the ciscuit=will-becompleted from;1ead wire 448*tothe lead'wire '45! which connects to the adjustable contact 452 of theresistance 446,- thereby'shunting out-a por- ;tion of:the:resistance-446 to increase thespeed of. the' fuel pump motor 431,in'order to provide the necessary-quantity-of fuel'for a proper'fu'elairmixture with the increased combustion air upply.

":The 'cam;member 425 has been'rotating 'at 1 a predetermined-rate,preferably a -minute cycle, and when the cam 426 has been-rotatedthrough T90 it will, at "the end-of the five-minute period,

engagellthe followerthrust member 453 to operate the arms 422 andlii'iltoithe'swit'ches'fl I' and-4H respectively to break the tcircuitof*the timer .motor 4!! and of the igniter M4. Although the circuit to thetiming "motor' 4l'Tisioroken at-the ,r'elay switch 4&8 upon .opening of"switch 4H which deenergizes the. relay coil 40?, theswitch '42 lprovides a safety:control toassure-stopping of the timing motor 4!!inxthe event relay switch 408 should fail to open. .Uponoperationasabove described, either at low or'highfuel, consumption vwillnot .be aifected by the.time ofoperation of follower member 453 bycam426. Whenit is desired to stop operationo'f the burner,"the-switchoperating member 4'lll'is-inoved totheposition .shown in the drawinginwhich switch'arm'4fl2 engages the fixed contact 454 so thatthetimin'gmotor MT is reenergized from thebattery'404 throughthe'following'circuit: From switch contact 454, through lead wire45'5'toilthe closedcam iswitch 429ian1d thencewiallead-wire 4'56*to"thetiminglmotonlea'd wire 423. Accordingly, ifjduringthe. interval ofreinstateditimermotor opera- ;tion Lthe combustion air ;pressure ihasdecreased below I the predetermined "blower pressure at which ram switch343I -remakes circuitbetweeni lead wires 434 and 435; theblower'motor43c will ,again' vbe placedin operation to providescavengingair'forthe combustion chamber. Upon the .termination of thereinstatedoperating'periodof will engage the follower member 421 to openthe cam switches 428 and 429 to break the circuits of and stop theblower motor 430 and the timing motor 4H respectively and halting orstopping the cam 426 in its position for the start of anotherlburnerlheating period when desired.

What isrclaimed and zris desiredptol'be secured by'Letters Patent is:

1. A heating apparatus comprising an electric'ally driven blower forsupplying combustion air, EaGCiYCllitF'fOT'TSaidTbIOWBI, an electricallydriven pump forlsupplying fuel for combustion, a circuit for"said pump;an electrically driven timing motorpzamcircuit for-said timing motor. acam oper gated rby saidzvmotor, hot wire ignition means for :Tthesupplied fuel, a circuit for said ignition amea-ns;arrelaysswitchcontrolling the circuit of said motor and having its coil in seriescircuit with said ignition means, a pump controlling relay switch havingan operating coil, a blower and '-'-pum-p --sv;r'itch opera-ted -"bysai'd cam 1 :upon stai'ting of ==said 'motor aanidccontrolling :the-l'circuits of said "pump and said blower, said I cam acting uponpredetermined running of said'motcr to open "said" blower andpumpswitch, arpairr:of normally closed switches controlling the-"circuitof said motor-and the=:circuit rofisaid-ignition means arid- -movable:toopen position byisai'dcam upon predetermined 'running :of said "motor,:a double-throw switch operable in one positionzto close the circuits 0fsaid r-elay'coiland :saiot oper- -dting 'coil-::arid :operable in the:other position .to close a circuitin 'shuntavithzsaid =cam'opened'motor switch f thereby to frein'state operation of said timing motorforpredeterminc'd Lclosure :of the-blower circuitp and a switchropened'vbys'said cam' to deenergize saidtiming motor: upon:o.pen-

ing of said blower-"switch by" said :cam.

'2. A heating apparatus *comprisingcanfelectri- "caliydriven blower 'fonsupplyingccmbustion;air, a circuit i for" said blower, an :electricallyr-driizan pump for supplying fuel for combustion, low and high-speed'circuitsTorsaid 'pumppan electrically driven timing motor, "a circuitfor 1 said :timing *motor, a cam operated :by' said motor, rhot'wireignition means 'for the supplied :fuel, ea :circuit "for saidignitionmeans,aa'irelayrswitchcontrolling the circuit of said motorand:having its'coil *in seiies circuit with said ignition 'means,:arelay switch having an'oper-ating' coilrearrdhavingnormally opencontacts controlling the lower speed circuit of said pHmpE'fQr low specdoperationand having normally 'open xcontacts :controiling "the highspeedcircuit of said pumpfforhighspeed operation, a 1 pressure "responsiveswitch fhaving i normally closed r contacts controlling the circuit 'ofsaidblower'and having normally openicontacts controlling the circuit to:said high speed: pump open contacts; said responsivetswitch 'acting-zatpredetermined increased combustionair pressure to open itsnormally'close'd contacts and "to :close its normally open-contacts, 9axblower'and pump switch operated by SZiClECEJm uporrstarting. of saidnrctcr an'clucontrollingcthe circuitszof said pump and saidblcwenasaidmam acting'lipongpredetermined runningro'f; sai'dimotorrto.opensaidzblower and ipump switch, zay pair of normally closedzswitchesmontrol'lingithenircuitioisa-idzmotoraand thei'circuitzofzsaid.ignition means-and movableto *open position I-by :said :cam uponpredetermined "running 'of sisaid :motor, .a fiouble-lthrow ."switchroperableinwne position ;to ;,close..the:.-circuits of--s-aid-relay1coil anrlzsaidz-operatingc coil and; operable in the otherpositionatovclose-aicircuitlin 15 minutes of the timing *mQtor'M-"I; thecam' 426" ?Shimt with.saidicam;cpenedrmo on wi v y to reinstateoperation of said timing motor for by said cam.

FRED B. AUBERT.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Carlson July 12, 1927 Number 6 Name Date DArche June 12, 1928Booth Dec. 4, 1928 Parker Sept. 13, 1932 McCabe Nov. 29, 1932 Fox Sept.25, 1945 Bower Mar. 25, 1947 Smoot Aug. 17, 1948 Aubert Oct. 11, 1949

